Leighton Holdings chief executive officer Hamish Tyrwhitt and chief financial officer Peter Gregg have been terminated from their positions at the company, effective immediately, as majority shareholder Hochtief sweetens its offer to lift its holding in the construction group.

Mr Tyrwhitt will be replaced by Hochtief CEO Marcelino Fernandez Verdes, who has been appointed on terms and conditions to be determined by the board.

Hochtief said earlier this week it wanted to lift its representation on Leighton's board, and Leighton has agreed to Hochtief's request for the termination of the executives, recognising Hochtief could achieve board control at the May 19 annual general meeting.

Leighton and Hochtief have entered a bid implementation agreement, with Hochtief increasing its offer to $22.50 per share for three out of eight shares, compared with an offer of $22.15 per share earlier this week.

The offer follows negotiations between Hochtief and Leighton's independent non-executive directors, who pressed the majority shareholder to make a takeover offer for all shares, which Hochtief declined.